IFMA

A Portion of the plannable area on a floor that can be assigned to occupants or functions.

Term used to describe Floor Common Area excluding corridors on multi-tenant floors. Service areas that are part of the basic functions of the building.

A term used to expresses the Gross Area of a floor less the area occupied by the thickness of the exterior walls.

Load-bearing platforms between floors suitable for equipment and mechanical use but not for occupancy by personnel except for maintenance purposes. found most frequently in laboratory and medical building types. This is not the same as mezzanine space.

Term used to describe corridors on multi-tenant floors or their functional equivalent for full-floor occupants.

Refers to corridors and walkways within the Usable Area of a tenant or department required for access and egress to/from all Assignable Areas. 

A portion of an enclosed floor area that is open to the floor below. Used in the International Facility Management Association.